August, 2016 - SUPPORT Summary of a systematic review | print this article |

What are the effects of interventions to improve adherence to medication?

The potential benefits of effective medications may not always be achieved if patients do not take them as prescribed. Adherence is defined as the extent to which a patient follows the instructions given for a prescribed treatment. Many adherence interventions are intended to assist patients with completing this task.


Key messages

 

  • It is uncertain whether interventions to increase adherence to short-term treatments im-prove adherence or patient outcomes.
  • Interventions aimed at increasing adherence to long-term treatments may improve adher-ence, but it is uncertain whether they improve patient outcomes.
  • Most of the included studies assessed complex interventions with multiple components in high-income countries.

- Adherence interventions may be difficult to implement in low-income countries where health systems face greater challenges.

Background

Poor adherence reduces treatment benefits when treatment responses depend on following a therapy dosage and schedule. This is a problem given that low adherence to prescribed treatments is very common. Non-adherence may have numerous causes, including problems with a regimen (e.g. adverse effects), poor instructions, poor provider-patient relationships, poor patient memory, patients contesting the need to be treated, or the inability of patients to pay for treatment.

Given the multi-faceted dimension of poor adherence, a range of possible interventions can be used, such as providing more instructions for patients, counselling and patient empowerment, automated telephone or computer-assisted patient monitoring, manual telephone follow-ups, family interventions, ways to increase the convenience of care, simplified dosing, involvement of patients in self-monitoring, reminders, alternative methods of pill packaging, dose-dispensing units of medication and medication charts, reinforcements or rewards, different medication formulations, crisis intervention (e.g. for attempted suicide), direct observation of treatments, lay health mentoring, augmented pharmacy services, psychological therapy, mailed communications and group meetings.



About the systematic review underlying this summary

Review objectives: To summarise the effects of interventions to help patients follow prescriptions for medications.

Types of What the review authors searched for What the review authors found

Study designs & interventions

Randomised trials evaluating interventions to improve adherence with prescribed, self-administered medications.

78 trials evaluating 93 diverse interventions.

Participants

Patients who were prescribed medication for a medical disorder (including psychiatric), but not for addictions.

Patients with several different chronic conditions including hypertension (12 studies), schizophrenia or acute psychosis (10), asthma or chronic obstructive pulmonary disease (COPD) (11), rheumatoid arthritis (2), hyperlipidaemia (3), depression (4) and HIV (12).

Settings

Any setting.

Many different settings and venues were included. Trials were conducted in the USA (30 studies), UK (14), Spain (5), Canada (8), Australia (3), the Netherlands (3), China (3), France (2), Mexico (1), Norway (1), Italy (1), Sweden (1), Ghana (1), Denmark (1), Republic of Ireland (1), United Arab Emirates (1), Switzerland (1) and Malaysia (1).

Outcomes

Medication adherence and patient outcomes.

9 studies on short-term and 71 on long-term treatments measuring adherence and patient outcomes.

Date of most recent search: February 2007.

Limitations: This is a systematic review with moderate limitations related to how the results were synthesized.

Haynes RB, Ackloo E, Sahota N, et al. Interventions for enhancing medication adherence. Cochrane Database of Systematic Reviews 2008, Issue 2. Art. No.: CD000011.

Summary of findings

An update of this review, published in 2014, included 109 new randomized trials, bringing the total number of included studies to 182. The interventions differed widely and the authors did not classify studies according to the type of intervention. Instead, a narrative focused on the results of 17 studies with low-risk of bias and a database of the 182 studies (without any synthesis of the findings) was provided. We therefore have not prepared a SUPPORT Summary of the updated review. Only five of the studies in the updated review found an improvement in both medicine adherence and clinical outcomes, and no common characteristics for their success could be identified. Overall, even the most effective interventions did not lead to large improvements in adherence or clinical outcomes.

This previous review found 78 studies conducted in many different settings, most of which were in high-income countries. Nine studies addressed interventions to improve adherence to short-term treatments, and 71 to long-term treaments. The studies evaluated very different types of interventions.

 

1) Interventions to improve adherence to short-term treatments

Nine studies evaluated 10 different interventions to increase adherence in very diverse conditions. The interventions evaluated were: the provision of more detailed instructions to patients (4 studies), the use of dose-dispensing units of medication (1), counselling about the target disease of the patients (3), the use of different medication formulations (1) and augmented pharmacy services (1)

  • It is uncertain whether interventions to increase adherence to short-term treatments improve adherence or patient outcomes. The certainty of this evidence is very low.

Interventions to improve adherence to short-term treatments

People:  Patients with several different medical conditions.
Settings
:  Many different settings.
Intervention
: Interventions to improve adherence to short-term treatments.
Comparison
: Any.

Outcomes Impact Certainty of the evidence
(GRADE)

Adherence

Several quite simple interventions increased adherence, but the effects were inconsistent across the studies. Fewer than half of the interventions showed benefits.

Very Low

Patient outcomes

Several quite simple interventions improved patient outcomes, but effects were inconsistent across the studies. Fewer than half of the interventions showed benefits.

Very Low

GRADE: GRADE Working Group grades of evidence (see above and last page).

 

2) Interventions to improve adherence to long-term treatments (more than 6 months)

71 studies evaluated 81 different interventions to increase adherence in very diverse conditions, including: asthma and chronic obstructive pulmonary disease (12 studies), hypertension (12), diabetes (6), HIV (12), rheumatoid arthritis (2), dyslipidemia (5), mental health conditions (14), epilepsy (1), heart failure (1) and ischemic heart disease (1). Some studies focused on specific medications, such as oral anticoagulant therapy (1) and contraception (1). Two studies evaluated interventions to increase adherence to complex regimens in the elderly.

  • Interventions aimed at increasing adherence to long-term treatments may slightly improve the adherence to medications. The certainty of this evidence is low.
  • It is uncertain whether interventions to increase adherence to long-term treatments improve patient outcomes. The certainty of this evidence is very low.

 

Interventions to improve adherence to long-term treatments

People:  Patients with several different conditions.
Settings
:  Many different settings.
Intervention
: Interventions to improve adherence to long-term treatments.
Comparison
: Any.

Outcomes Impact Certainty of the evidence
(GRADE)

Adherence

Only 34 of 81 interventions were associated with improvements in adherence. Almost all of the interventions that were effective were complex and included combinations of: more convenient care, information, reminders, changing dosing schedules, self-monitoring, reinforcement, counselling, family therapy, psychological therapy, crisis intervention, manual telephone follow-ups, and supportive care. Even the most effective interventions did not lead to large improvements in adherence.

Low

Patient outcomes

Only 26 of 81 interventions led to improvement in at least one patient outcome. Almost all of the interventions that were effective were complex and included combinations of: more convenient care, information, reminders, changing dosing schedule, self-monitoring, reinforcement, counselling, family therapy, psychological therapy, crisis intervention, manual telephone follow-ups, and supportive care. Even the most effective interventions did not lead to large improvements in patient outcomes.

Very Low

GRADE: GRADE Working Group grades of evidence (see above and last page).

Relevance of the review for low-income countries

Findings Interpretation*
APPLICABILITY
  • The review identified 78 studies evaluating interventions to improve adherence to medications. The studies differed according to the type of setting, the conditions targeted, the type of medication and the duration of treatment.
  • Most studies were conducted in high-income countries.
  • It is uncertain whether the majority of the effects of the interventions improved medication adherence. 
  • Almost all the interventions that were found to be effective were complex, and included combinations of interventions, and the size of their effects on patient outcomes is uncertain.
  • Complex adherence interventions may be difficult to implement in low-income countries
EQUITY

The studies did not directly address the issue of equity.

  • Factors causing poor adherence often impact upon disadvantaged populations more (e.g. poor memory, inability to pay for the treatment). Therefore, effective interventions to increase adherence might selectively help such populations achieve the benefits of effective medication.
  • There might be differential effects of interventions to improve adherence according to gender, education, religion, socioeconomic status, and racial/ethnic factors. However, the review did not find evidence to support or refute such differential effects.
ECONOMIC CONSIDERATIONS

The included studies provide no data about the cost of the interventions.

  • The cost-effectiveness of these interventions cannot be determined based on the information available. 
MONITORING & EVALUATION
  • In the majority of studies, adherence was measured using self-reporting or other methods that were not reliable.
  • This review found evidence that some interventions may lead to better patient outcomes
  • Studies measuring adherence but not measuring patient outcomes were not included in this review.
  • There is little information about adverse effects or costs in the included studies.
  • Measuring adherence is a complex task and frequently used methods (e.g. self reporting) may not be accurate. Objective measures provide a more accurate measure of true adherence but they are more expensive.
  • Future research should focus on those interventions that are most promising.
  • Interventions to increase adherence consume resources and attempts to increase adherence can have adverse effects (such as the loss of privacy and autonomy and increased adverse effects of treatment). It is important not only to monitor effects, but also to monitor adverse effects and costs.
  • Randomised trials addressing the above issues in low-income countries are needed.
*Judgements made by the authors of this summary, not necessarily those of the review authors, based on the findings of the review and consultation with researchers and policymakers in low-income countries. For additional details about how these judgements were made see: http://www.supportsummaries.org/methods

Additional information

Related literature

Nieuwlaat R, Wilczynski N, Navarro T, et al. Interventions for enhancing medication adherence. Cochrane Database of Systematic Reviews 2014, Issue 11. Art. No.: CD000011.

 
Horne R, Weinman J, Barber N, et al. Concordance, adherence and compliance in medicine taking: a scoping exercise. London: NCCSDO; 2005.

 
Schroeder K, Fahey T, Ebrahim S. Interventions for improving adherence to treatment in patients with high blood pressure in ambulatory settings. Cochrane Database of Systematic Reviews 2004, Issue 3. Art. No.: CD004804.

 
Vermeire EIJJ, Wens J, Van Royen P, et al. Interventions for improving adherence to treatment recommendations in people with type 2 diabetes mellitus. Cochrane Database of Systematic Reviews 2005, Issue 2. Art. No.: CD003638.

 
Volmink J, Garner P. Directly observed therapy for treating tuberculosis. Cochrane Database of Systematic Reviews 2007, Issue 4. Art. No.: CD003343.

 
Schedlbauer A, Davies P, Fahey T. Interventions to improve adherence to lipid lowering medication. Cochrane Database of Systematic Reviews 2010, Issue 3. Art. No.: CD004371.

 
Schedlbauer A, Davies P, Fahey T. Interventions to improve adherence to lipid lowering medication. Cochrane Database of Systematic Reviews 2010, Issue 3. Art. No.: CD004371.

 
Mahtani KR, Heneghan CJ, Glasziou PP, Perera R. Reminder packaging for improving adherence to self-administered long-term medications. Cochrane Database Syst Rev. 2011, Issue 9. Art. No.: :CD005025.

 
Al-aqeel S, Al-sabhan J. Strategies for improving adherence to antiepileptic drug treatment in patients with epilepsy. Cochrane Database of Systematic Reviews 2011, Issue 1. Art. No.: CD008312.


    This summary was prepared by

    Gabriel Rada. Unit for Health Policy and Systems Research, Faculty of Medicine, Pontificia Universidad Católica de Chile

    Conflict of interest

    None declared. For details, see: www.supportsummaries.org/coi

    Acknowledgements

    This summary has been peer reviewed by: Brian Haynes, Jimmy Volmink, and Hanna Bergman

    This review should be cited as

    Haynes RB, Ackloo E, Sahota N, et al. Interventions for enhancing medication adherence. Cochrane Database of Systematic Reviews 2008, Issue 2. Art. No.: CD000011.

    The summary should be cited as

    Rada G. What are the effects of interventions to improve adherence to medication? A SUPPORT Summary of a systematic review. August 2016. www.supportsummaries.org

    Keywords

    evidence-informed health policy, evidence-based, systematic review, health systems research, health care, low and middle-income countries, developing countries, primary health care, medication adherence, medication compliance, medication non-compliance, medication non-adherence, patient compliance, treatment refusal.



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